The present invention relates to a room temperature-curable organopolysiloxane composition which can be cured by the mechanism of dealcoholation condensation reaction to give a cured rubbery elastomer having good adhesion to the surface of a substrate such as plastics.
As a recent trend, devices and instruments in electric and electronic industries are desired to be designed in more and more compact forms for several reasons. In addition, it is also a recent trend that the housings of such devices and instruments are shaped of a plastic resin such as polycarbonate, polybutylene terephthalate, acrylic, nylon, ABS, polyvinyl chloride and the like thermoplastic resins. The industries of building construction and vehicles for trnsportation are also along this trend of increasing use of plastics in many parts and the plastics used in these fields include acrylic resins, polycarbonate resins, polyvinyl chloride resins and the like.
It is usual that the plastic-made parts are jointed together by use of a silicone sealant or a room temperature-curable organopolysiloxane composition for adhesive bonding and sealing while good adhesion of a silicone sealant to the surface of a plastic-made part is obtained only by the indispensable use of a primer. Since most of the primers for such a use are supplied in the form of a solution in an organic solvent, a very serious problem is caused by the use of a primer on to the surface of a plastic-made part which absorbs the organic solvent to be eventually cracked in the adhesively bonded or sealed part. Therefore, it has been eagerly desired to develop a room temperature-curable organopolysiloxane composition which can exhibit good adhesion on to the surface of a plastic-made body without using a primer when it is cured in contact with the substrate surface.